The present invention relates to an ink cartridge for storing therein ink to be supplied to a recording apparatus that prints letters, images or the like.
An inkjet printer that prints letters, images or the like is designed to form an image with minute droplets of ink. An ink cartridge storing the ink to be supplied to the inkjet printer is detachably mounted on a main body of the printer, so that the ink cartridge can be removed from the main body for replacement, when the stored ink has been consumed.
The ink cartridge includes an ink chamber for storing the ink therein, an ink supply port for supplying the ink to the printer and an air intake port for introducing air to the ink chamber or the like. At the point of sale in general, the entirety of the ink cartridge is vacuum-packed, and the ink chamber is depressurized.
Conventional ink cartridges, for example one disclosed in Japanese Patent Application Laid-Open No. 9-85963 (1997), include valves at the ink supply port and the air intake port respectively, to prevent leakage of the ink out of the ink chamber, such that once the ink cartridge is mounted on the printer two projecting portions provided in the printer press the respective valves upward, thus to open the valves. Air is introduced into the ink chamber once the projecting portion of the printer opens the valve that has kept the air intake port closed, upon mounting the ink cartridge on the printer.
The ink supplied to the printer through the ink supply port is ejected on a printing paper from a plurality of ejection nozzles incorporated in a printer head through an ink path of the printer, to thereby form a letter, an image or the like. When ejecting the ink through the ejection nozzles, the ejection status of the ink through the ejection nozzles has to be maintained in a constant level for securing a desired printing quality. For such purpose, the droplet of the ink formed at the ejection nozzles is led to have a concave curved portion, called a meniscus, on its liquid surface.